DIVERGENT PATHWAYS FOR DELTA-AMINOLEVULINIC-ACID SYNTHESIS IN 2 SPECIES OF ARTHROBACTER

Secretion of coproporphyrin III by suspensions of Arthrobacter photogo nimos and A. globiformis facilitated analysis of the paths of synthesi s of delta-aminolevulinic acid, the precursor of tetrapyrroles. Sensit ivity of coproporphyrin accumulation to gabaculine and incorporation o f C-14 from [1-C-14]glutamate indicated that suspensions of A. photogo nimos synthesized delta-aminolevulinic acid from glutamate by the wide spread C5 pathway. In contrast, A. globiformis cells switched from pre dominantly the C5 pathway for delta-aminolevulinic acid synthesis in e arly exponential phase cultures to delta-aminolevulinic acid synthase in stationary phase cultures.